Airplane propeller



Nov. 6, 1945. B. BERGEN 2,388,464

AIRPLANE PROPELLER Filed June 13, 1944 Patented Nov. 6, 1945 UNITED ,STATES QFFICE;

AIRPLANE PROPELLER Bernhard Bergen, Washington, D.. C.v

ApplicationJuner 13, 1944', SerialNo; 540,069 e. claims. (o1. 17a-reti) iin/'.er-1tirm relates to certain new and useful" improvements in airplane propellers.

An, object ofi the invention is -to provide an airplane propeller preferably constructed of light gauge metal to effect a reduction in the weight of the propeller,` the propeller blades per se and the radial arms carrying the same that project from a propeller shaft being or hollow construction.

` A further andV important object of the inventionis to provide an all metal fire-proof' screw propeller for an airplane that is designed in a manner to operate with a minimumA of noise duringrotation thereof.

A still further object of the invention is to provideA an airplane propeller of the foregoing character wherein radial arms projecting from a propellerA shaft and carrying propeller blades at their-"outer ends are of tubular pipe-like construction and are adapted to receive a metallic cable which does not materially increase the weight Qt s uch arms but provides a reinforcing element for-said arms and protection against bullets, shrapnel or the like.

With the above and other objects in view that will become apparent as the nature of the invention is better understood, the same consists in the novel form, combination and arrangement of parts hereinafter more fully described, shown in the accompanying drawing and claimed.

In the drawing:

Figure 1 is a front elevational view of an airplane propeller constructed in accordance with the present invention, the same being partly broken away and shown in section,

Figure 2 is a longitudinal sectional View taken on line 2--2 of Figure 1, showing the spaced wall construction of the propeller blades per se,

Figure 3 is a sectional view taken on line 3-3 of Figure 1 showing the mounting ofthe propeller per se on one end of a propeller shaft, and

Figure 4 is an end elevational view of the propeller showing the angularly disposed propeller blades per se at opposite ends of the supporting arms.

Referring more in detail to the accompanying drawing, the reference numeral 5 designates the propeller shaft of an airplane that carries at its forward end a transversely extending arm designated in general by the reference character 6 and said arm at its outer ends carries propeller blades designated in general by the reference character The connection between the supporting arm 6 and the propeller shaft 5 comprises a head mem- `ber'formed'of' apairof disks 8'v and 9 that are connected' byV an equatorial rib I'U to provide a headj structure substantially H'shaped` in cross section as shown in Figure 3; but it is to be understood that said supporting head may have the disk portions 8` andl 9' thereof selectively formed integral with the rib I0 instead of the unitary structure illustrated. The connection between the supporting head` and propeller shaft 5 preferablyincludes a weld joint H3, but other means of* connection may be substituted forsuch` joint;

The arm 6 that extends transversely of the forward end of the propeller shaft 5y is formed ofa pair of parallel tubular-membersV lf2 and said tubular'members at points substantially midway said head and the outer endsl thereofV are twisted intov overlapping relationshipas indicated' at I3' and have thel propeller blades 'I perse secured to the outer ends thereof, with the twou propeller blades'- positioned at desirable` relative angles for proper propulsion purposes. As illustrated in Figure 1\=,` thet'ubul'armembers I2' of.- the propeller blade supportingarm 6 are spot-welded together as at' t4? for the reinforcementv of said'.V tubular members in proximity of the twisted portions I3 thereof.

Each propeller blade 'l is of the chambered type and comprises spaced top and bottom walls I5 and I6 with opposite ends deflected toward each other forming relatively sharp ends I6, the open sides of said top and bottom walls I5 and I6 being closed by correspondingly shaped side walls I1, all of said walls being secured together in any appropriate manner as by welding or the like. 'I'he outer ends I2a of the tubular members I2 pass through a side wall I 'l of the propeller blade I and at their terminal ends abut the inner face of the opposite side wall l'I, said ends I2a being secured to the propeller blade by nut and bolt combinations I8 extending transversely through the top and bottom walls I5 and I6 of the propeller blade and the housed end portions I2a of the tubular members I2, it being understood that other means of attachment may be employed to present smooth uninterrupted surfaces at the outer sides of the walls I5 and I6. As illustrated the leading end Ia of .the propeller blade is spaced a greater distance from the connection of the blade with the arm 6 than the trailing end 'Ib as shown in Figures l and 2.

The connection between the arm yIi and head mounting therefor, as shown in Figures 1 and 3, has the rib I Il of the head disposed between the spaced tubular members I2 and the arm is lanchored to the head by means of the nut and bolt combinations I9 associated with the disk members 8 and 9 of the head at opposite sides of the spaced rib l0, this arrangement of elements providing a strong and substantial support for the propeller blade on the propeller shaft.

The arm 6 and blades 1 are preferably constructed of light gauge metal for the reduction of weight and the particular relative angles of the propeller blades per se results in the operation of the propeller with a minimum of noise. Without materially increasing the weight of the quires, to place a solid metallic cable 20 within the tubular members I2 of the arm 6 to provide Y a reinforcement for said arms and a protection against bullets, shrapnell and the like.

From the above detailed description of the invention, it is believed that the construction and operation thereof will at once be apparent and while there is herein shown and described the preferred embodiment of the invention, it is nevertheless to be understood that minor changes may be made therein Without departing from the spirit and scope of the invention as claimed.

I claim:

1. In an all-metal airplane propeller of the character described, and in combination with a propeller shaft, an arm connected to and extending transversely of the forward end of the shaft, a propeller blade mounted on and extending transversely of each of the outer ends of said arm, said arm including a pair of tubular mem- ;bers and said blades being of shell-like form, the connection of said arm with the shaft including a pair of disk-like members, a rib spacing the members and disposed between said tubular members with one of said disks secured to said shaft and nut and bolt combinations 'carried by said disk members and associated with said tubular member for retaining the latter in position, and a steel cable extending through each tubular member to reinforce the same 2. In an all-metal airplane propeller of the character described, and in combination with a. propeller shaft, an arm connected to and extending transversely of the forward end 0f the shaft, a propeller blade mounted 0n and extending transversely of each of the outer ends of said arm, saidarm including a pair of tubular members and said blades being of shell-like form, the connection of said arm with the shaft including a pair of disk-like members, a rib spacing the members and disposed between said tubular members with one of said disks secured to said shaft and nut and bolt combinations carried by said disk members and associated with said tubular member for retaining the latter in position, and 4a steel cable extending through each tubular member to reinforce the same, and said tubular member being twisted outwardly of the connection with said shaft to present the propeller` blades in relative angular relations.

3. In an al1-metal airplane propeller of the character described, and in combination with a propeller shaft, an arm connected to and extending transversely of the forward end of the shaft, a propeller blade mounted on and extending transversely of each of the outer ends of said arm, said arm including a pair of tubular members and said blades being of shell-like form, the connection of said arm with the shaft including a pair of disk-like members, a rib spacing the members and disposed between said tubular members with one of said disks secured to said shaft and nut and bolt combinations carried by said disk members and associated with said tubular member for retaining the latter in position, `and a steel cable extending through each tubular member to reinforce the same, the outer ends of the tubular members extending into said propeller blades and cross bolts for anchoring said ends therein.

BERNHARD BERGEN. 

